The exemplary embodiments relate to a finisher for an image forming apparatus such as a copier, a printer, or a facsimile machine. The finisher may perform any number of operations, such as, predetermined punching, stapling, etcetera, for each medium, such as a sheet, on which an image is formed by the image forming apparatus.
The related art includes a number of finishing operations. For example, in the related art, a finisher for performing punching includes a punch mechanism (puncher), which moves to a predetermined position based on size information of a medium, such as a sheet of paper (or other medium to be punched). For example, the puncher is positioned at a particular location along a sheet of paper based on the width of the paper. A plurality of detectors are placed corresponding to a plurality of sheet sizes, and a puncher is moved into position based on the detection information for performing punching on a specific sheet. This related art finisher requires a plurality of detectors, which increases the cost of the apparatus. In addition, from a design standpoint, it may be problematic to provide sufficient detectors to cover a number of sheets having similar sizes, due to, for example, space constraints. Furthermore, determining where to place each of the plurality of detectors to preferably correspond to the plurality of different sheet sizes becomes problematic.
Another related art finisher only utilizes one detector. This sole detector detects the width of a sheet (or other medium), and the position at which a puncher is moved is determined in response to the detected width of the sheet. Punching is performed under the condition determined for each sheet. However, use of the sole detector necessitates that the puncher be reset for each sheet to match the size of the sheet. Resetting the puncher for each sheet takes time, and thus may reduce productivity of high-speed imaging forming apparatuses.